November 10, 2003ORLANDO, FL (AHA)
– A
“universal stem cell clone” found in adult bone marrow
regenerated blood vessels and heart muscle, according to
research reported at the American Heart Association’s Scientific
Sessions 2003.
The cells, called human bone marrow-derived multipotent stem
cells (hBMSC), were implanted into animal hearts where they
formed multiple cell types.
The hBMSC improved animals’ heart function, said the study’s
lead author, Young Sup Yoon, M.D., Ph.D., assistant professor of
medicine at Tufts University School of Medicine in Boston.
“This study is exciting because it is the first to show that
human bone marrow includes a clonal stem cell population that
can differentiate into both vessels and heart muscle," Yoon
said. "These cells can regenerate the essential tissues of the
heart.” This finding comes from animal and laboratory research.
Such stem cells might be used to regenerate damaged hearts
for people who have acute and chronic heart failure. They also
might help people with hypertension, diabetes or other blood
vessel diseases.
The researchers found that these stem cells didn’t belong to
any previously known bone marrow-derived stem cell population
(such as hematopoietic cells, the source for all types of blood
cells or mesenchymal cells that give rise to cell types like
bone and cartilage).
These adult bone marrow stem cells have been shown to
differentiate into all three so-called “germ layers.” The
three germ layers of cells in early human development are the
beginnings of the body’s tissues and organs. Differentiation is
the term that describes the process in which stem cells change
into these specialized cells.
To find out if these unique stem cells would repair heart
damage, the researchers induced a heart attack in rats and
introduced the hBMSC into heart tissue around the affected
area. They injected unselected bone marrow cells and saline as
controls.
Heart function was measured by non-invasive echocardiography
and by a pressure transducer, an instrument at the tip of a tiny
catheter that is threaded through an artery into the heart to
measure blood pressure and heart function.
Heart function after 28 days was better in rats that received
the hBMSC than in the rats that received total bone marrow cells
or saline.
The transplanted hBMSC differentiated into heart muscle cells
and blood vessel cells.
Important proteins that encourage blood vessel growth, called
angiogenic cytokines, also increased or were newly expressed.
The same thing occurred with factors important to the
development of the heart in utero, called cardiac transcription
factors. The number of heart and vessel cells also increased
after hBMSC transplantation.
Co-authors are Andrea Wecker, M.S.; Lindsay Heyd, B.S.; Jong
Seon Park, M.D., Ph.D.; Allison Hanley, B.S.; and Douglas W.
Losordo, M.D.